Air-conditioning apparatus of the induction type



L. CHIEREGATTI April 19, 1960 AIR-CONDITIONING APPARATUS OF THE.INDUCTION TYPE 2 Sheets-Sheet 1 Filed July 1, 1958 Fig. 6

United tates Patent 2,932,956 Patented Apr. 19, 1960 AIR-CONDITIONINGAPPARATUS OF THE INDUCTION TYPE Luigi Chieregatti, Milan, ItalyApplication July 1, 1958, Serial No. 746,030 Claims priority,application Italy August 23, 1957 2 Claims. (Cl. 62-296) This inventionrelates to an air-conditioning apparatus of the induction type.

Air-conditioners of the induction type comprise a primary air supplychamber to which air flows at high speed and high static pressure from afan, if desired in a preconditioned state, air fiowing from the supplychamber through a valved opening to silencing and expansion chamberprovided on a wall thereof with injection nozzles. The primary airenters through the nozzles at high speed a mixing chamber and inducesfrom the surroundings through a heat exchanger extending along saidmixing chamber a secondary air stream with which it forms a mixturewhich is supplied through a port to the room to be conditioned.

The main object of this invention is to provide an airconditioner of thetype referred to above, improved to combine a satisfactory operation andinexpensive installation, low cost of manufacture and moderate height,whereby it is suitable for installation below the windows of modernbuildings with low sills.

An object of this invention is to provide a special arrangement of thesupply chamber, silencing and expansion chamber and mixing chamber.

In conventional apparatuses the supply and expansion chambers are mostlyvertically superposed to provide an apparatus of moderate width, whichis, however, of considerable height and unsuitable for installation inrooms with modern glazings and low sills.

In the improved apparatus the above mentioned drawback is removed byarranging the supply chamber and silencing and expansion chamber side byside in horizontal direction in a lower portion of the apparatus,thereby forming a box of approximately rectangular cross-sectional shapewhich, when the apparatus is hung to a Wall or placed on the floor, hasits longer side extending parallel to the floor. The mixing chamber issituated at the middle of the top portion of the apparatus, leaving twolateral regions free. The latter enclose the heat exchanger facing thefront of the apparatus and fluid pipes supply the heat exchangeraccommodated by a recess facing the back of the apparatus.

In addition to efliciently reducing the overall size of the apparatus ina transverse direction, the improved arrangement is advantageous,inasmuch as it permits, more particularly with a plurality ofapparatuses in a side-byside arrangement, full freedom in securing tothe wall the supply pipes for the heat exchangers and arranging in saidpipes the taps for the various apparatuses which are then placed infront of the pipes assembled and insulated.

Such arrangement of the supply pipes for the heat exchangers is furtheradvantageous in that it avoids laying said pipes in the floor or ceilingwhere the pipes would hardly be accessible and a useful space would belost in a vertical direction for disguising the pipes.

A further characteristic feature of the improved apparatus resides inthe use of the heat exchanger of small height, preferably not exceeding20 cm., without detrimentally reducing its front area and heat exchangesurface, the heat exchanger being therefore, its front area being thesame, greater in length than present constructions.

In addition to limiting the height of the apparatus, its induction ratiois thereby improved over apparatuses of the same exchange surface areaarranged on a smaller length and greater height.

The primary air volume and front area of the heat exchanger being thesame, the improved apparatus affords a heat exchanger of reduced heighthaving, with respect to conventional apparatuses with a heat exchangerof greater height, an improved induction ratio, that is an improvedratio of induced air to primary air, for the following reasons:

(1) The primary air quantity per unit of length of the heat exchanger isreduced.

(2) The contact surface between the primary air and induced air isincreased through the possibility of increasing the number of nozzles.

(3) The spacing of nozzles can be increased within certain limits.

The secondary air volume is further increased because the heat exchangerof greater length and smaller height increases the available area forthe flow of secondary air at the region nearest the nozzles, at whichthe induction effect is greatest.

A further object of this invention is to arrange the nozzles and heatexchanger on a wall sloping towards the room through an angle of 5 to 15to the horizontal. The injection nozzles and heat exchanger are mountedin parallel relationship, their axes being perpendicular to said wall,so that they are inclined forwardly towards the room through 5 to 15 tothe vertical. This results in air mixture issuing from the apparatuswhich is spontaneously forwardly directed towards the room, therebyenhancing the air circulation in the room and removing from thesurroundings of the window, tapestry regions and like the conditionedair lamination; without resorting to a set of longitudinal bafile wingswhich have to be provided on the outlet port in present conditioners inwhich, the nozzle axes extending in a vertical plane the condi tionedair lamination tends to issue in a vertical direction.

The wall carrying the nozzles and to which the heat exchanger isattached, extends forwardly beyond the heat exchanger to form a sumpconnecting and discharging any condensate from ambient moisture whichmight be formed as a result of improper operation of the plant. Thissump is therefore situated at a freely accessible region outside theheat exchanger on the front of the apparatus, the water collectingtherein by dripping along the inclined wall.

The drawbacks of conventional apparatuses in which the sump for thecondensate is situated beneath the heat exchanger are therebyeliminated, said drawbacks consisting in that the sump is difficult toclean, the exchanger plate ends which, with a considerable condensation,are submerged in water are liable to oxidize, the re-evaporation beinghardly possible in that the re-evaporation surface is partly screened bythe overlying heat exchanger. The improved apparatus affords anextensive re-evaporation surface which is fully exposed and will not inany case involve the plates on the heat exchanger which are thereforeconstantly kept dry. The extensive re-evaporating surface will in mostcases make the condensate discharge system superfluous.

The slope of the wall carrying the nozzles and heat exchanger leavesbetween the heat exchanger and suction strainer for the secondary air atriangular space free, which is usefully employed for arranging the airfilter and thermostat valve, thereby avoiding the necessity ofincreasing the depth of the conditioner.

A further feature of this invention resides in that the passage betweenthe primary air supply chamber and silencing and expansion chamber islocated at the lower portion of the partition between both chambers,said passage extending throughout the length of the apparatus. Thepassage extending throughout the length of the a paratus allows of airdisplacement from its inlet into the silencing and expansion chamber upto the nozzle plane at very low rate of speed free from longitudinaldelivery currents. This circumstance as well as the arrangement of theair passage at the lowest portion of the partition between the high andlow pressure chambers, hence most remote from the nozzles, permits ofarranging in the expansion chamber an excellent extensive silencinglabyrinth, through which air moves evenly without swirling, thisinsuring a thorough noiselessness and a highly uniform delivery beneaththe nozzle plane.

Further characteristic features and advantages of this invention will beeasily understood from the appended description which refers to theaccompanying drawings showing a preferred embodiment of the inventiongiven by way of example only. On the drawings:

Figure 1 is a perspective view of the apparatus,

Figure 2 is a longitudinal section of view of the apparat'us on lineIIII of Figure 3,

Figure 3 is a cross-sectional View of the apparatus on line III-III ofFigure 2,

Figure 4 is a part cross-sectional view of the apparatus showing afurther embodiment of the silencing labyrinth,

Figure 5 is a detail view of a plate of the heat exchanger and Figure 6is a cross sectional view of the heat exchanger plate.

The air-conditioner shown in Figures 1 to 3 comprises a basic bodyincluding the supply chamber 1, control valve 2, silencing and expansionchamber 3 extending adjacent the chamber 1 in the lower portion of theapparatus, injection nozzles 4, mixing chamber 5, heat exchanger 6 withautomatic or manually operated adjusting valve 7 therefor and air filter8. The apparatus is completed by a cabinet comprising a frame 9 having alaterally oif-set top lid 10, a front panel 11, an inlet strainer 12 andan outlet strainer 13.

The apparatus shown in Figures 1 to 3 can be encased in either avertical or horizontal position, the covering including appropriateencasing structures provided with strainers 12 and 13.

The primary air flows to the supply chamber 1 through a hose 39connected with a central conditioning station, reaches the silencing andexpansion chamber 3 through the adjusting valve 2 and passage 14 which,according to this invention, is situated in the lower portion of thechamber and extends throughout the length thereof. The primary airreaches through the silencing labyrinth, established by the bafiies 15,the injection nozzles 4 through which it is injected in the mixingchamber 5 in which it induces from the surrounding through the inletstrainer 12, filter 8 and heat exchanger 6 a secondary air stream withwhich it becomes mixed, the mixture issuing through the outlet strainer13 to the room to be conditioned.

The silencing labyrinth 15 is formed by one horizontal and two verticalbattle sections extending throughout the length of the chamber, the airtherein being twice deflected through 90 and twice deflected through180.

In the modification shown in Figure 4 the silencing labyrinth is formedby three horizontal baffles causing the air to be deflected three timesthrough 180.

According to this invention the chambers 1 and 3 extend lengthwiseparallel with each other in a horizontal plane'at the lower region ofthe apparatus. The mixing 'chamber likewise extends longitudinally inthe middle reg-ion of the upper portion of the apparatus. The heat 6exchanger is of small height preferably not exceeding 20 cm.

The wall 16 carrying the injection nozzles 4 is inclined to thehorizontal through an angle on, the slope amounting to 5 to 15 Inaddition to the nozzles the wall 16 carries a seating for the heatexchanger and forms by an extension towards the front the sump 17collecting the condensed water. Both, nozzles 4 and heat exchanger 6,which extend parallel with each other and perpendicular to the slope 16,are inclined through angle on to the vertical. 1

The control valve 2 comprises a valve member 18 which can be calibratedby means of a calibrating device designated as a whole by 19, whichbecomes accessible upon removal of the strainer 13 through the topopening in the mixing chamber 5, so as to adjust the static pressurebeneath the nozzles plane, hence the inflow of primary air to thenozzles. A remote control 24, which is easily fitted to the left orright of the apparatus serves 'for closing or opening the valve uponopening of the lid 10 on the frame 9 beside the outlet strainer '13.Through the lid the adjusting valve for the heat exchanger and itscontrol, in the case of a manual control, or the thermostat, in the caseof an automatic valve, are also accessible. In this case, the thermostatvalve 34 is arranged in the triangular clearance between the inletstrainer 12 and heat exchanger 6.

The valve member 18 and control and calibrating means therefor aredisclosed in a copending application Ser. No. 745,931 filed July 1, 1958by the same applicant.

Figures 5 and 6 show in plan and sectional view, respectively, a detailof the plates of the exchanger 6. The plates are formed with ribs 38adapted to increase both the plate surface and turbulence of air throughthe exchanger, thereby improving heat exchange.

Figure 2 shows the special arrangement of theside walls 31 which closethe lower portion of the apparatus enclosing the supply and expansionchambers. The side walls are retracted with respect of the extreme endsections of the heat exchanger and leave two clearances free in which itis possible to arrange, without increasing the overall length of theapparatus, pipes 32 for connection, if desired, of the sum 17 to thedischarge system and device 33 for levelling the apparatus on installingon the floor or to the wall.

Figures 1 to 3 further show the special construction of the cabinetframe 9. The frame has a longitudinal plane of'syrnmetry (Fig. 3) andcan therefore be assembled to easily carry out an apparatus with a lidfor the control of the adjusting valves for the heat exchanger andprimary air on the left or right side respectively.

It will be understood that embodiments and constructional details can bevaried from the example described and shown within the principle of thisinvention without departing from the scope thereof.

What I claim is:

1. In an air conditioning apparatus of the induction type a horizontallyelongated air box of a substantially rectangular cross-sectional shape,a mixing chamber overlyingthe air box, a longitudinally extendingpartition in the air box subdividing the interior of the latter into aplenum chamber and a silencing-expansion chamber, the last namedchambers being vertically co-extensive in the box and being arranged ina mutual side-by-side relationship, a valve-controlled primary airpassage from the plenum chamber to the silencing-expansion chamberextending through the said partition lengthwise thereof, a pluralityofbaffles extending in the silencing-expansion chamber lengthwise of thelatter whereby, when seen in cross-sectional view, thesilencing-expansion chamber is of a labyrinth shape, and primary airnozzle means connecting the labyrinth with a bottom section of theoverlying mixing chamber.

2. In an air conditioning apparatus of the induction type a horizontallyelongated air box of a substantially rectangular cross-sectional shape,a mixing chamber overlying the air box, a longitudinally extendingpartition in the air box subdividing the interior of the latter into aplenum chamber and a silencing-expansion chamber, the last namedchambers being vertically coextensive in the box and being arranged in amutual side-by-side relationship, a primary air passage from the plenumchamber to the silencing-expansion chamber extending through the saidpartition lengthwise of the latter, a valve member for controlling thesaid primary air passage arranged in the plenum chamber, a plurality ofbaffies extending in the silencing-expansion chamber lengthwise of thelatter whereby, when seen in cross-sectional view, the silencingexpansion chamber is of a labyrinth shape, and primary air nozzle meansconnecting the labyrinth with a bottom section of the overlying mixingchamber.

References Cited in the tile of this patent UNITED STATES PATENTS2,324,313 Meyerhans July 13, 1943 FOREIGN PATENTS 784,828 Great BritainOct. 16, 1957

